David Chandler jumps the shark

[Tony Szamboti]

Really??
Ok, I must say I am surprised to read this. I admit at this point that I have never myself studied the motion of the NT's top carefully frame by frame and assumed that both towers had tilt from the start. Got to look into this... Anyone else going to comment?

Do you agree that the South Tower started to tilt from the first moment on? I believe ozeco's oft-posted animated gif with the pivot overlayed is ST.

The South Tower does tilt immediately at collapse initiation. Its early behavior is not applicable to the North Tower.

 

[Oystein]

assumed that both towers had tilt from the start. Got to look into this...

Alright, as a starting point, here is Major_Tom's "WTC1 Accurate Collapse History":

"1) Deformations: Inward bowing of the south face
2) Earliest detectable creep movement of the antenna and northwest corner
3) Appearance of ~87th fl S face ejections
4) Appearance of 95th fl W face ejection
5) Visible downward movement begins: Concave deformation of the roofline, antenna drops before north or west perimeter walls
6) Columns fail over tilt of less than 1 degree, appearance of 98th fl ejections and 105th floor ejections
7) Appearance of 77th fl W face ejections
8 ) Splitting of all perimeter walls: All visible upper parts fall out and over lower parts
9 ) Southward sliding of upper portion
10 ) Dis-integration of upper portion"​

I think you, Tony, don't agree with this chronology, or do you?

If you do, at which point in this chronological list would you expect to see a jolt caused by vertical and axial impact?

If "1) Deformations: Inward bowing of the south face" is accurate (happens before all else), then I claim that this already implies a (minimal) tilt, as inwardly bowed columns cannot fill their original vertical space - the south face above the inward bowing must already have moved down by something.

If you insist that 1) is not true^[1], then tilt has already occurred as 6) is observed: "Columns fail over tilt of less than 1 degree"
Your expected but MJ should thus happen before 6).



^[1] I'd like to avoid debating the veracity of this point at this time, in order to not lose the plot. Just let's indicate for all that follows whether you/we assume IB before all else, or not.

 

[JSanderO]

The South Tower does tilt immediately at collapse initiation. Its early behavior is not applicable to the North Tower.

Once there is downward motion there was also some amount of lateral displacement and there was a bit of asymmetry of the disengagement from the lower section which induced some tilt and perhaps rotation. The damage to 1wtc was more symmetrical from the get go and it proceeded in a more symmetrical manner about the north south axis. But it WAS organic and when the top was released it was slightly tilted. Same mechanisms in play... different locations... different movements.

 

[Oystein]

The South Tower does tilt immediately at collapse initiation. Its early behavior is not applicable to the North Tower.

Ok, Thx

 

[Dave Rogers]

It has also then been explained to you that after losing their orthogonal support the perimeter walls would behave as a slender sheet and provide some resistance but less than that required to support the static load above them. Thus the upper section would bend them down and outward while accelerating at 1G - resistance from the slender sheet.

I'm not denying that the resistance from the perimeter columns was less than would have been required to support the upper block. However, this resistance was not negligible - it was, according to your analysis in which only the perimeter columns resisted collapse, equal to about a third of the weight of the top block. You have repeatedly stated that, for the lower structure to offer significant resistance to collapse, a jolt must be observable unless the structure is destroyed with explosives. Yet the perimeter column sheets, which you have admitted were not being destroyed with explosives, no jolt was observed. Therefore your own statements disprove your theory.

Quite simply, you can't have it both ways. You've argued, to the point of abuse directed at anyone who disagrees with you, that a jolt must be observed for the lower structure to resist collapse to a significant degree. You have stated that no such jolt was observed. You have also admitted that the perimeter sheets resisted collapse to a significant degree. These statements are mutually contradictory.

I feel this must be painfully obvious to everyone except you (and your fellow truthers, who will blindly support the most absurd positions however in disagreement with their own as long as they contradict a fire induced collapse model, as you will theirs). A question for everyone else: Is this as embarrassingly obvious to you as to me?

Dave

 

[WilliamSeger]

Bazant embellishes the kinetic energy by using free fall through the first story with 8.52 m/s vs. the actual 6.13 m/s. This alone doubles the kinetic energy due to it being squared.

Really? Of course, Bazant worked with energy rather than velocity, and your assertion here shows why that's a much better approach. Your assertion implies that half of the gravitational potential energy was absorbed or dissipated. Please explain where it went (and if all you have is more bare assertions, don't waste the keystrokes). Then, please explain how that much energy was absorbed if the columns were actually blown out with magical silent explosives. It seems to me you're arguing yourself into more cognitive dissonance.

He then nearly doubles the mass by using maximum design load vs. actual service load. In essence, he quadrupled the actual kinetic energy.

Not having design details, Bazant used an estimate for the mass. (It appears that you're referring to Gregory Ulrich's estimate, and when I looked through that a while back, I didn't see anything added for office contents.) But it doesn't matter because you're ignoring an important fact: Bazant also used that same estimate to approximate the design of the columns, so if his mass estimate was high, then so were his column design estimates, which invalidates your next assertion:

Bazant also underestimated the energy absorption capacity of the columns below by more than half.

How much energy could be absorbed seems to be a contentious issue, but my opinion is that it's an issue best settled by actual experts, which disqualifies your opinion. But really, in this case, there's no point in arguing about that because you're ignoring a much more important fact: the energy absorption of the columns below is almost irrelevant to what actually happened. Very few of the columns were actually crushed, because shearing the floors away from the columns required less energy. You continue to demonstrate that you have never really understood the logic of Bazant's "limit case" analysis.

These facts show Bazant's analysis is bogus.

Actually, comparing the real facts to your bare assertions tells me that your analysis is bogus. For example:

When the actual energy of the moving upper section is calculated and the actual energy absorption capacity of the columns below is calculated it shows a fall through one or two stories would have arrested in fairly short order. We calculated two stories after the first impact.

Which actually implies that those calculations must be wrong; otherwise, Verinage demolitions wouldn't work. In fact, conventional demolitions which only blow out columns on one or two floors wouldn't work, because they depend on gravity to do the rest. It also defies logic that if the falling mass and velocity were both increasing after each impact, which they certainly were, that any number of impacts would eventually arrest the collapse. How many positive numbers do you have to add up to get a negative number? If your calculations defy both logic and observation, a rational person would consider the possibility that those calculations might be wrong.

Even if the energy absorption was not fully efficient there should have been a very serious deceleration.

And here we go again with the "missing jolt" cognitive dissonance, based on the very analysis that you now say is wrong. That horse is long since deceased, Tony.

ETA Re: "A question for everyone else: Is this as embarrassingly obvious to you as to me?" Yes.

 

[Grizzly Bear]

But really, in this case, there's no point in arguing about that because you're ignoring a much more important fact: the energy absorption of the columns below is almost irrelevant to what actually happened. Very few of the columns were actually crushed, because shearing the floors away from the columns required less energy. You continue to demonstrate that you have never really understood the logic of Bazant's "limit case" analysis.

<snipped for brevity>

ETA Re: "A question for everyone else: Is this as embarrassingly obvious to you as to me?" Yes.

His error is of course much more basic than this. Bazant's model did not try to explain reality. All it concluded was that if the collapse could not be arrested under the most ideal impact scenario, then it was never going to arrest in lesser benchmarks.

Tony can discuss what he finds wrong with Bazant's work until the cows come home, so long as it's limited to the model, such as concluding that Bazant's model assumptions might not have been THAT absolute, but taking the model beyond it's limits and misrepresenting the intentions of a modeled limit case is a fatal enough flaw that it removes the necessity to follow his train of discussion. I think it completely a waste of time to entertain his mixing of reality and theoretical model.

Thus far the only meaningful response to this contention that's been given is a suggestion that professional background trumps peoples' ability to read the first paragraph of an abstract in a paper.

 

[Oystein]

A question for everyone else: Is this as embarrassingly obvious to you as to me?

Dave

To me, an admitted amateur when it comes to engineering, this is not immediately obvious - it required some explaining.

Several here, including you, have explained it very well, while Tony Szamboti resorts to attacks against the arguers when he sees that he can't even address the arguments of amateurs.

 

[Oystein]

...
Not having design details, Bazant used an estimate for the mass. (It appears that you're referring to Gregory Ulrich's estimate, and when I looked through that a while back, I didn't see anything added for office contents.) But it doesn't matter because you're ignoring an important fact: Bazant also used that same estimate to approximate the design of the columns, so if his mass estimate was high, then so were his column design estimates, which invalidates your next assertion:
...

I am not saying you are wrong, because I don't know; but I have my doubts and advise that you re-read Szuladzinski, Johns & Szamboti (2013) "Some Misunderstandings Related to WTC Collapse Analysis" to verify if Tony gets the magnitude of Bazants estimation error wrong.

 

[jaydeehess]

The South Tower does tilt immediately at collapse initiation. Its early behavior is not applicable to the North Tower.

So alignment/misalignment of columns only is an issue with the North tower. Are we now going to say that only the north tower shows such definitive proof of demolition?

 

[GlennB]

A question for everyone else: Is this as embarrassingly obvious to you as to me?

Dave

I can "sort of" see his pov. To explain why only "sort of" you'd have to look into Szamboti's muddled brain and see how he's picturing it. His idea - perhaps - would be that core columns were severed causing the collapse initiation, meaning a 1-storey collapse until core column ends could meet again, necessarily producing a 'jolt'.

But this didn't apply to the exterior columns, which were never severed (apart from some fiddling with the corner columns). Thus we see a relatively ordered <g acceleration over that one storey as the exterior columns were overwhelmed, followed by the cataclysmic meeting of core columns.

If that's how he's seeing it (and that's a mile from being clear) it still fails because the 'symmetrical' early stages of collapse are just as entitled to bring falling exterior columns into axial alignment as it did the broken core columns. Yet there's zero evidence of demolition of the outer columns and still no jolt. By his own line of argument those exterior columns should have produced a jolt *or* shown clear evidence of demolition.

I think.

tl;dr
He's talking bollocks and just can't bear to stop.

 

[Tony Szamboti]

I'm not denying that the resistance from the perimeter columns was less than would have been required to support the upper block. However, this resistance was not negligible - it was, according to your analysis in which only the perimeter columns resisted collapse, equal to about a third of the weight of the top block. You have repeatedly stated that, for the lower structure to offer significant resistance to collapse, a jolt must be observable unless the structure is destroyed with explosives. Yet the perimeter column sheets, which you have admitted were not being destroyed with explosives, no jolt was observed. Therefore your own statements disprove your theory.

Quite simply, you can't have it both ways. You've argued, to the point of abuse directed at anyone who disagrees with you, that a jolt must be observed for the lower structure to resist collapse to a significant degree. You have stated that no such jolt was observed. You have also admitted that the perimeter sheets resisted collapse to a significant degree. These statements are mutually contradictory.

I feel this must be painfully obvious to everyone except you (and your fellow truthers, who will blindly support the most absurd positions however in disagreement with their own as long as they contradict a fire induced collapse model, as you will theirs). A question for everyone else: Is this as embarrassingly obvious to you as to me?

Dave

Dave, your word twisting is extraordinary. I have never said that to have resistance there must be a jolt.

I have said that in a natural collapse there must be a jolt to overcome the reserve strength, which could handle many times the static load, because it contains a factor of safety.

The reality here is that the perimeter was cut at its corners and the resistance it then provided as a slender sheet was less than sufficient to handle the static load. There would be no jolt in that case as the perimeter walls would be overloaded as a single slender sheet being bent over and downward and if the static load can't be supported it will accelerate through the lower than g resistance.

 

[pgimeno]

I feel this must be painfully obvious to everyone except you (and your fellow truthers, who will blindly support the most absurd positions however in disagreement with their own as long as they contradict a fire induced collapse model, as you will theirs). A question for everyone else: Is this as embarrassingly obvious to you as to me?

It certainly is for me. If the perimeter descent is not expected to produce a jolt, the core shouldn't either. I was shocked when I saw Tony say that about the perimeter columns.

 

[Dave Rogers]

There would be no jolt in that case as the perimeter walls would be overloaded as a single slender sheet being bent over and downward and if the static load can't be supported it will accelerate through the lower than g resistance.

So what you're saying is that, if the load carrying ability of the lower structure is reduced to the point where it can no longer support the load above it, it will collapse without a jolt, right?

Dave

 

[ozeco41]

Really??
Ok, I must say I am surprised to read this. I admit at this point that I have never myself studied the motion of the NT's top carefully frame by frame and assumed that both towers had tilt from the start. Got to look into this... Anyone else going to comment?

I wasn't going to - I've addressed all aspects of Tony's nonsense many times. And much of the recent discussion has been addressing points that Tony has made and playing the game within the false scenario that Tony has imposed.

We know Tony is wrong so rather than keep repeating the proofs of his errors why not simply explain what really happened. Tony's false assertions should then be obvious in contrast.

So on the issue of tilt the claim I would make is this:

Assertion re "Tilt" - Tilt is irrelevant to understanding of the collapse mechanism. It is a consequence of the mode of failure NOT a cause. It enters the sequence AFTER the key bits of mechanism are past.

A persistent basic error in Tony's claims is that he gets the sequence and the logic arse about ("backasswards"??).

This is the outline of the reasoning to explain what "really happened" for both WTC1 and WTC2. All stated as bare assertions - I can demonstrate proof of each one and the whole sequence if there is any interest in reasoned discussion.

Assertion A - Both Twin towers collapsed in a mechanism that can be explained in two key stages viz:
(i) "initiation stage" from aircraft impact through accumulating damage (Including allowing for CD at this stage - it makes little difference to the argument)
(ii) "progression stage" - what followed once the "Top Block(s) started to move downwards; AND
-- we can fine tune the details of the stage boundary and sub stages if and when we need to.

Assertion B - Neither tower initiated collapse immediately following impact - both had a delay - then a cascade failure THEREFORE some "trigger" initiated failure after the delay;

Assertion C1 (conditional) If there was CD it was the trigger;

Assertion C2 - absent any proof of CD the trigger event MUST have been failure of the first column in a cascading sequence heat induced axial overload. (I'm aware of a JSanderO preferred alternative - the result is the same - column fails in compressive axial loading.)

Assertion D - when that first column failed in axial overload the load it was carrying - the structure above - moved downwards. Reducing the space for the column which was buckling/bending/whatever. So the ends for that one column MUST miss.

Assertion E - complete the sequence for more columns UNTIL the capacity to support the Top Block is removed. Top Block starts to "fall". All columns surviving to that point fail instantly.

Assertion F - ONE cause of tilt is that during this cascading failure sequence more columns fail on one side of the building causing tilt towards that side.

BUT

Assertion G - to get to that stage the ends of every failing column have already "missed" (Or - anticipating an obvious "yes but" - are in a situation where progress to "missing' cannot be averted.)

So Assertion H - "tilt" cannot either cause or prevent "axial impact" of column ends BECAUSE axial impact has already been missed by the time there is tilt from this cause. (And the other causes of tilt come even later in the collapse so they are also "too late" and "irrelevant".)

And Assertion I - "Tilt" occurs AFTER columns have failed - therefore is not a factor in CAUSATION of column failure.

And that is far enough for most of the issues we still see confusion over.

Reasoned, objective discussion invited. For obvious reasons taking those assertions in order - moving to the next assertion after the preceding one is agreed.

Meanwhile your final points Oystein:

Do you agree that the South Tower started to tilt from the first moment on? I believe ozeco's oft-posted animated gif with the pivot overlayed is ST.

The first thing in the failure mechanism - when it restarted after the post aircraft impact delay - was column vertical failure ( I know - another assertion I can prove if necessary. ) "Tilt" at that early stage of "initiation" was a consequence of column failure. It came after column failure. Column failure is what caused tilt - not vice versa. And don't make too much of the "pivot overlayed" - inherited from the originator Achimspok who used the graphic for a different purpose...lets not go there. )

( So - repeating the theme - we need to think through what really happened - and not get trapped into working within the limits of T Szamboti's false sequences and false scenarios.)

And - yes - the graphic I have been using was WTC2. And I have stated repeatedly that the principles for WTC1 were the same. Anyone who follows through the outline of argument I have just stated as a sequence of assertions should readily see why.

 

[ozeco41]

The corner connections of the perimeter walls were indeed severed with charges. The video clearly shows very rapid focused ejections on both sides of the corner where the spandrel plates were bolted to the corner.

I feel this must be painfully obvious to everyone except you (and your fellow truthers, who will blindly support the most absurd positions however in disagreement with their own as long as they contradict a fire induced collapse model, as you will theirs). A question for everyone else: Is this as embarrassingly obvious to you as to me?
Dave

It sure is for me. The foundation error - or deliberate debating trickery - is that Tony continues to mix and match his false model misappropriated from Bazant with comment and assertions about the real event. They are two fundamentally different mechanisms. Tony's assumed version of Bazant did not and could not happen. Why do we keep humouring his fantasies by playing along with his false scenario?

These comments of yours warrants highlighting Dave:

Therefore your own statements disprove your theory.

Quite simply, you can't have it both ways. You've argued, to the point of abuse directed at anyone who disagrees with you, that a jolt must be observed for the lower structure to resist collapse to a significant degree. You have stated that no such jolt was observed. You have also admitted that the perimeter sheets resisted collapse to a significant degree. These statements are mutually contradictory.

So true. He self contradicts so often.

AND - members seem to be letting Tony get away with his "modified claims". No problem if he changes his mind BUT - one examples - with every assertion he makes that core columns were cut by CD Tony is explicitly denying "Missing Jolt".

 

[JSanderO]

Excellent summary Ozzie... the tilting IS the columns failing kinda... if they didn't fail the top would be suspended in mid air. The tilt is because the columns did not fail all at once and so capacity was lost favoring one side.

I think there was more tilt in 2wtc because the column failure progressed from the SE to the NW while in 1wtc in progressed east and west from the center. The antenna drop is the tell tale that the center was the weakest part and first to completely give way in 1wtc.

Obviously the destruction by heat was dynamic and chaotic and hence there would be no perfect symmetry. But it was remarkably symmetrical and with little tilt because the the location of the initial damage and the way failures propagated outward from there.

 

[Tony Szamboti]

So what you're saying is that, if the load carrying ability of the lower structure is reduced to the point where it can no longer support the load above it, it will collapse without a jolt, right?

Dave

That is right.

 

[ozeco41]

Excellent summary Ozzie...

Thank you Sander.

the tilting IS the columns failing kinda... if they didn't fail the top would be suspended in mid air.

YES - because if the Top Load did not move down the column would not be crushed in to buckling/bending/whatever >. wouldn't fail. And "moving down" means the column cannot still be in the space at original length...etc etc ...all those facts linked in a circle of interrelated cause<>effect. Easy to understand if you think about it one column at a time. Because for each and every column that failed in axial overload it has to be true. People confuse themselves by trying to think about the whole Top Block - treating it as one integral structure and losing the mental plot. Sure it was one integral structure BUT you cannot think it through coming at the reasoning that way - sooner or later you must ask:

Q: "What happened to each column that failed?"

A: "The Top Block overloaded the column and doing so it moved down and squeezed/crushed it into a reducing height space. So the ends must miss at some point in that inevitable progression."

As I've said for years it is so "bleedingly obvious" - once you "get" it. But you have to reach and pass the "eureka point" and it ain't easy for left brainers who cannot process thinking without maths. So many engineers, accountants and e.g. Tony - who persists in asking for maths or calcs or FEA when the error is in logic or describing what you want to apply maths to. "Show me your calculations" "Calculations for what?" "I cannot say because you wont show your calculations". [/TrutherLogic]

Tony Sz's classic error and falsehood on the "whole top block" approach being this one recently repeated:

The upper section had enormous inertia and there were no lateral loads sufficient to move it out of alignment until it fell a few stories and started tilting due to eccentric loading.

Utter nonsense including arse about logic. We know the Top Block moved downwards in the early stages of collapse. For that downwards movement to occur each column made its own arrangements for the Top Bit to miss the Bottom Bit. There was no "committee of the whole" with all members of the Top Block agreeing that they wouldn't fail until the whole block moved sideways. Facetious explanation aside - stupid assertions deserve facetious responses - there are several fatal errors in that nonsense claim by Tony.

 

[Tony Szamboti]

Thank you Sander. YES - because if the Top Load did not move down the column would not be crushed in to buckling/bending/whatever >. wouldn't fail. And "moving down" means the column cannot still be in the space at original length...etc etc ...all those facts linked in a circle of interrelated cause<>effect. Easy to understand if you think about it one column at a time. Because for each and every column that failed in axial overload it has to be true. People confuse themselves by trying to think about the whole Top Block - treating it as one integral structure and losing the mental plot. Sure it was one integral structure BUT you cannot think it through coming at the reasoning that way - sooner or later you must ask:

Q: "What happened to each column that failed?"

A: "The Top Block overloaded the column and doing so it moved down and squeezed/crushed it into a reducing height space. So the ends must miss at some point in that inevitable progression."

As I've said for years it is so "bleedingly obvious" - once you "get" it. But you have to reach and pass the "eureka point" and it ain't easy for left brainers who cannot process thinking without maths. So many engineers, accountants and e.g. Tony - who persists in asking for maths or calcs or FEA when the error is in logic or describing what you want to apply maths to. "Show me your calculations" "Calculations for what?" "I cannot say because you wont show your calculations". [/TrutherLogic]

Tony Sz's classic error and falsehood on the "whole top block" approach being this one recently repeated: Utter nonsense including arse about logic. We know the Top Block moved downwards in the early stages of collapse. For that downwards movement to occur each column made its own arrangements for the Top Bit to miss the Bottom Bit. There was no "committee of the whole" with all members of the Top Block agreeing that they wouldn't fail until the whole block moved sideways. Facetious explanation aside - stupid assertions deserve facetious responses - there are several fatal errors in that nonsense claim by Tony.

The lack of rigor and logic here is startling. You are indulgent beyond imagination.